The exceptionally high prevalence of diastrophic dysplasia in Finland has enabled us to analyse the foot deformities of 102 patients at their first orthopaedic evaluation and classify 204 feet into five categories. The most common finding (43%) was a foot with tarsal valgus deformity and metatarsus adductus; 37% showed either equinovarus adductus (29%) or equinus (8%) deformities. At the first examination 13% showed metatarsus adductus deformity alone, and 7% were clinically normal. The expression 'club foot', generally used for the foot deformity in diastrophic dysplasia is a misnomer. There is a wide spectrum of deformities, some of them specific for the condition.

A prospective study was made of 119 children with transient synovitis or any other cause for synovial effusion and elevated intra-articular pressure. During a follow-up of one year not one case of Perthes' disease was diagnosed and the late clinical and radiographic changes were minimal with moderate overgrowth of the femoral head in 33% and widening of the joint space in 14.2%. Our results do not support the widely accepted concept that Perthes' disease develops as a result of the period of elevated intra-articular pressure found in transient synovitis. Further research into this and Perthes' disease should follow the premise that they are two different diseases without any aetiological connection.

Fifty-one infants with limited abduction of the hip and acetabular dysplasia were, between 1969 and 1975, treated with abduction-adduction exercises, administered by the parents; no abduction devices were used. In 1983 a follow-up examination was carried out on 41 of these patients. Although at birth these children had characteristics similar to patients with congenital dislocation of the hip, none of their hips dislocated. At birth acetabular measurements showed that half the children had severe dysplasia and the other half slight dysplasia; the difference between the affected and the healthy hips was significant. At follow-up the gait was normal in all the patients. Movements at the hips were symmetrical and within normal limits in all but one patient. The acetabular angle, the centre-edge angle, the shaft-neck angle, the hip ratio, and the size of the femoral head were the same on the previously affected side as on the normal side. Nineteen of the children followed up had preferred lying on one side and dysplasia of the upper hip had developed. The significance of the sleeping position on the development of acetabular dysplasia is discussed.

A total of 67 patients with 94 resistant club feet were treated operatively as soon after birth as all other postnatal problems could be excluded, the mean age of the patients being 12 days. No treatment was attempted before operation. The results, after a follow-up period of a minimum of two years (mean 4.4 years) are comparable with the best published results. This method of treatment has many advantages but cannot be recommended for general use without reservations.

Spontaneous correction of deformity is produced by bone remodelling during the period of growth. The purpose of this experimental study was to find out in which phase and to what extent asymmetrical epiphysial growth participated in the correction of an experimentally produced deformity. Transverse wedge osteotomy was performed in the legs of twenty growing mongrel dogs, the fragments being fixed with bent AO-plates. From radiographs taken at intervals of two weeks the epiphysial and axial angles were measured. Nine dogs were given tetracycline ten to twenty days before death and the cut surfaces were photographed in reflected ultra-violet light. It was found that epiphysial growth played an important role in the remodelling process. This factor accounted for roughly half of the total correction and averaged 12-5 degrees during the observation time of 160 days. The greatest correction occurred during the first weeks. Correction of the epiphysial angle took place with acceleration of growth.